Drug therapy for diabetic dyslipoproteinaemia: a practical approach

Simvastatin in non-insulin-dependent diabetes mellitus: effect on serum lipids, lipoproteins and haemostatic measures

The clinical efficacy of the 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMGCoA) reductase inhibitor simvastatin in the treatment of hypercholesterolaemia in non-insulin-dependent diabetes (NIDDM), was examined in a double-blind placebo-controlled study of 6 months in 70 patients with NIDDM (age 25-70 years), of whom 57 were randomised to placebo (29 patients) or simvastatin for 6 months, following a 3-month run-in on diet. Patients were hypercholesterolaemic (7.8 (7.6-8.0) (mean (95% confidence intervals)) mmol/l simvastatin vs. 8.0 (7.7-8.5) mmol/l placebo) and mildly hypertriglyceridaemic (2.6 (2.2-3.0) simvastatin vs. 2.9 (2.3-3.5) placebo). Other lipid measures and estimates of glycaemic control and haemostasis were similar in both groups. There were no significant changes in lipids, haemostatic factors, or measures of glycaemic control in the placebo treatment group. Conversely by the end of 24 weeks, simvastatin produced a 28% reduction in cholesterol (to 5.6 (5.0-6.2) mmol/l (P < 0.001)), a 38% reduction in LDL cholesterol (from 5.5 (5.4-5.6) mmol/l to 3.4 (2.8-4.0) mmol/l, P < 0.001), a 15% reduction in triglyceride (to 2.2 (1.8-2.6) mmol/l, P < 0.05, and a 9% rise in HDL (from 1.16 (1.07-1.25) to 1.23 (1.14-1.32) mmol/l, P < 0.05). Improvements in apolipoprotein B (apo B) (-28%, P < 0.001), the LDL cholesterol to apo B ratio (-20%, P < 0.001), and apo A1 (+15%, P < 0.001) were recorded. There were no effects upon fibrinogen, factor VII activity, factor VIII activity, or measures of glycaemic control (fasting glucose, insulin, C-peptide, or HbA1).(ABSTRACT TRUNCATED AT 250 WORDS)

Atherogenic profiles in insulin-dependent diabetic patients and their treatment

Longitudinal studies have shown a large excess of cardiovascular mortality in insulin-dependent diabetic patients (IDDM) as compared to non-diabetic controls. Although diabetes appears to be an independent cardiovascular risk factor, increases in total and LDL-cholesterol together with a decrease of HDL-cholesterol are more pronounced in diabetics with cardiovascular disease. The general opinion, however, derived from a large number of cross-sectional studies, is that in well-controlled IDDM lipoprotein abnormalities are modest and only slightly different from matched non-diabetic controls. Most of the studies, however, used absolute criteria based on consensus statements and do not take the internal relations of the lipoproteins into account. When atherogenic indices (such as the relationship between total cholesterol and HDL-cholesterol or the Apo A1/apo B quotient) are used, 20 to 30% of an IDDM population considered to be in clinically acceptable control have to be considered pathological. This observation is even more important since the recent Diabetes Control and Complications Trial has shown that, especially in the younger group of patients, significantly higher total cholesterol and triglycerides and lower HDL-cholesterol were observed. Especially in these patients can diet and drug intervention be the most useful in the prevention of cardiovascular disease. These data are consistent with the fact that more sophisticated techniques have previously shown atherogenic changes in the composition of the VLDL-particles and lipoprotein enrichment in apo B. Since these techniques are not easily available in the clinic one has to refer to more classical techniques and the use of above mentioned atherogenic profiles to decide treatment.

The effect of bezafibrate on very low density lipoprotein (VLDL), intermediate density lipoprotein (IDL), and low density lipoprotein (LDL) composition in type 1 diabetes associated with hypercholesterolaemia or combined hyperlipidaemia

Lipoprotein composition was examined in type 1 diabetic subjects with hypercholesterolaemia +/- hypertriglyceridaemia during a 3-month double-blind placebo controlled assessment of bezafibrate therapy. The predominant effect was on lipoprotein lipid content. In those with hypercholesterolaemia alone, bezafibrate significantly reduced the cholesterol (particularly esterified cholesterol) and triglyceride content of large very low density lipoprotein (VLDL) (Svedberg flotation units (Sf) 60-400) in comparison to the placebo group (P less than 0.05), and a trend towards a reduction in free and esterified cholesterol within the intermediate density lipoprotein fraction (IDL) (Sf 12-20) was noted. Low density lipoprotein (LDL) composition was unaltered and in general phospholipid and protein concentrations and cholesteryl ester/protein ratios within the lipoprotein fractions were unaffected. Large VLDL cholesterol and triglyceride concentrations in those with combined hyperlipidaemia were significantly decreased following bezafibrate therapy, both in comparison to placebo-treated subjects and to baseline concentrations (P less than 0.05). An additional significant reduction in small VLDL (Sf 20-60) free cholesterol was recorded (P less than 0.05). Average reductions of large and small VLDL protein of 50-56% were not significant because of wide variation in responses. Bezafibrate had no effect on the abnormal composition of IDL and LDL, characteristic of Type 1 diabetes, regardless of whether or not hypertriglyceridaemia was associated with hypercholesterolaemia. Its major action was to lower VLDL lipid concentrations, but it may also reduce the lipid content of intermediate density lipoprotein in Type 1 diabetes.

Screening for hyperlipidaemia in diabetes mellitus. Relationship to glycaemic control

Diabetic patients have an increased risk of developing cardiovascular disease which, in part, may be due to lipid abnormalities. Our aim was to establish from an initial screening programme what proportion of diabetic patients attending a routine diabetic outpatient clinic had hyperlipidaemia despite having good or acceptable glycaemic control. We screened 299 randomly selected diabetic patients to assess the prevalence of hyperlipidaemia and its relationship to glycaemic control. Twenty-eight per cent had hyperlipidaemia (defined as cholesterol greater than 6.5 mmol/L and/or non-fasting triglycerides greater than 3 mmol/L). Of these hyperlipidaemic patients, 71% had good or acceptable glycaemic control as defined by a glycated haemoglobin value of less than 10%. Approximately 40% of type 2 diabetic patients had body mass index values outside recommended targets indicating the potential of weight reduction in this group as a treatment modality. Our results indicate that the majority of hyperlipidaemic diabetic patients had good or acceptable glycaemic control, and as such these patients are potential candidates for specific lipid lowering therapy.

Double-blind placebo-controlled study of the effects of bezafibrate on blood lipids, lipoproteins, and fibrinogen in hyperlipidaemic type 1 diabetes mellitus

The effects of bezafibrate 400 mg day-1 or placebo administered for 3 months, were compared in 36 patients with stable Type 1 diabetes and hypercholesterolaemia and/or hypertriglyceridaemia. Baseline characteristics of the 17 bezafibrate- and 19 placebo-treated patients were comparable in most respects with the exception of concentrations of fasting serum triglycerides and blood glucose which were lower (NS) and plasma fibrinogen which were higher (p less than 0.05), in those later treated with bezafibrate. Serum cholesterol concentrations decreased after 3 months bezafibrate treatment (from 7.1(0.2) (SE) to 6.3 (0.3) mmol l-1, p less than 0.05), predominantly due to a reduction in low density lipoprotein (LDL) cholesterol (from 4.8(0.3) to 4.2(0.3) mmol l-1, p less than 0.05). Over the same period bezafibrate reduced serum triglycerides from 1.78 (95% Cl 1.23-2.57) to 1.26(1.02-2.09) mmol l-1 (p less than 0.05), and plasma fibrinogen from 4.1(0.2) to 2.9(0.2) g l-1, p less than 0.001. Serum apolipoprotein B and apolipoprotein (a) showed no statistically significant changes. Overall there was no change in high density lipoprotein (HDL) cholesterol. However, in patients who were initially hypertriglyceridaemic there was significant increase in the cholesterol content of HDL and the HDL2-cholesterol subfraction (both p less than 0.05). After 3 months treatment with bezafibrate, fasting blood glucose levels were reduced from 8.5(1.1) to 6.4(0.7) mmol l-1, p less than 0.05, without any change in glycosylated haemoglobin (9.2(0.4) to 9.1(0.5)%).(ABSTRACT TRUNCATED AT 250 WORDS)